SwiftFlutterSystemProxyPlugin.swift

import Flutter
import UIKit
import JavaScriptCore

public class SwiftFlutterSystemProxyPlugin: NSObject, FlutterPlugin {
  static var proxyCache : [String: [String: Any]] = [:]
  
  public static func register(with registrar: FlutterPluginRegistrar) {
    let channel = FlutterMethodChannel(name: "flutter_system_proxy", binaryMessenger: registrar.messenger())
    let instance = SwiftFlutterSystemProxyPlugin()
    registrar.addMethodCallDelegate(instance, channel: channel)
  }

  public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
    switch call.method {
    case "getDeviceProxy":
        let args = call.arguments as! NSDictionary
        let url = args.value(forKey:"url") as! String
        var dict:[String:Any]? = [:]
        if(SwiftFlutterSystemProxyPlugin.proxyCache[url] != nil){
            let res = SwiftFlutterSystemProxyPlugin.proxyCache[url]
            if(res != nil){
                dict = res
            }
        } 
        else 
        {
            let res = SwiftFlutterSystemProxyPlugin.resolve(url: url)
            if(res != nil){
                dict = res
            }
        }
        result(dict)
        break
    default:
      result(FlutterMethodNotImplemented)
    }
  }

  static func resolve(url:String)->[String:Any]?{
        if(SwiftFlutterSystemProxyPlugin.proxyCache[url] != nil){
            return SwiftFlutterSystemProxyPlugin.proxyCache[url]
        }
      let proxConfigDict = CFNetworkCopySystemProxySettings()?.takeUnretainedValue() as NSDictionary?
      if proxConfigDict != nil {
          if(proxConfigDict?[kCFNetworkProxiesProxyAutoConfigEnable] as? Int == 1){
                let pacUrl = proxConfigDict?[kCFNetworkProxiesProxyAutoConfigURLString] as! String?
                let pacContent = proxConfigDict?[kCFNetworkProxiesProxyAutoConfigJavaScript] as! String?
                if(pacContent != nil){
                    self.handlePacContent(pacContent: pacContent!, url: url)
                }else if(pacUrl != nil){
                    self.handlePacUrl(pacUrl: pacUrl!,url: url)
                }
            } else if (proxConfigDict![kCFNetworkProxiesHTTPEnable] as? Int == 1){
                var dict: [String: Any] = [:]
                dict["host"] = proxConfigDict![kCFNetworkProxiesHTTPProxy] as? String
                dict["port"] = proxConfigDict![kCFNetworkProxiesHTTPPort] as? Int
                SwiftFlutterSystemProxyPlugin.proxyCache[url] = dict
            }
        }
        return SwiftFlutterSystemProxyPlugin.proxyCache[url]
    }
    
    static func handlePacContent(pacContent: String,url: String){
        let proxies = CFNetworkCopyProxiesForAutoConfigurationScript(pacContent as CFString, CFURLCreateWithString(kCFAllocatorDefault, url as CFString, nil), nil)!.takeUnretainedValue() as? [[CFString: Any]] ?? [];
        if(proxies.count > 0){
            let proxy = proxies.first{$0[kCFProxyTypeKey] as! CFString == kCFProxyTypeHTTP || $0[kCFProxyTypeKey] as! CFString == kCFProxyTypeHTTPS}
            if(proxy != nil){
                let host = proxy?[kCFProxyHostNameKey] ?? nil
                let port = proxy?[kCFProxyPortNumberKey] ?? nil
                var dict:[String: Any] = [:]
                dict["host"] = host
                dict["port"] = port
                SwiftFlutterSystemProxyPlugin.proxyCache[url] = dict
            }
        }
    }

    static func handlePacUrl(pacUrl: String, url: String) {
    let _pacUrl = CFURLCreateWithString(kCFAllocatorDefault, pacUrl as CFString?, nil)
    let targetUrl = CFURLCreateWithString(kCFAllocatorDefault, url as CFString?, nil)
    var info = url
    withUnsafeMutablePointer(to: &info, { infoPointer in
        var context: CFStreamClientContext = CFStreamClientContext(version: 0, info: infoPointer, retain: nil, release: nil, copyDescription: nil)
        let unmanagedRunLoopSource = CFNetworkExecuteProxyAutoConfigurationURL(_pacUrl!, targetUrl!, { client, proxies, error in
            let _proxies = proxies as? [[CFString: Any]] ?? []
            if (_proxies.count > 0) {
                let proxy = _proxies.first { $0[kCFProxyTypeKey] as! CFString == kCFProxyTypeHTTP || $0[kCFProxyTypeKey] as! CFString == kCFProxyTypeHTTPS }
                if (proxy != nil) {
                    let host = proxy?[kCFProxyHostNameKey] ?? nil
                    let port = proxy?[kCFProxyPortNumberKey] ?? nil
                    var dict: [String: Any] = [:]
                    dict["host"] = host
                    dict["port"] = port
                    let url = client.assumingMemoryBound(to: String.self).pointee
                    SwiftFlutterSystemProxyPlugin.proxyCache[url] = dict
                }
            }
            CFRunLoopStop(CFRunLoopGetCurrent())
        }, &context)
        let runLoopSource = unmanagedRunLoopSource.takeUnretainedValue()
        let runLoop = CFRunLoopGetCurrent()
        
        CFRunLoopAddSource(runLoop, runLoopSource, CFRunLoopMode.defaultMode)
        CFRunLoopRun()
        CFRunLoopRemoveSource(CFRunLoopGetCurrent(), runLoopSource, CFRunLoopMode.defaultMode)
    })
}
    
    //For backward compatibility <= XCode 15
    static func getRunLoopSource<T>(_ runLoopSource: T) -> CFRunLoopSource {
        if let unmanagedValue = runLoopSource as? Unmanaged<CFRunLoopSource> {
            return unmanagedValue.takeUnretainedValue()
        } else {
            return runLoopSource as! CFRunLoopSource
        }
    }
    
}